[BOJ] 5052. 전화번호 목록

문제 원본 : https://www.acmicpc.net/problem/5052

5052번: 전화번호 목록

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Arrays;

public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int t = Integer.parseInt(br.readLine());
        String[] numbers = null;
        boolean isSucc;
        StringBuilder builder = new StringBuilder();

        while (t-- > 0) {
            int n = Integer.parseInt(br.readLine());
            numbers = new String[n];

            for (int i = 0; i < n; ++i) {
                numbers[i] = br.readLine();
            }

            Arrays.sort(numbers);

            isSucc = true;
            for (int i = 1; i < n; ++i) {
                if (numbers[i].startsWith(numbers[i - 1])) {
                    isSucc = false;
                    break;
                }
            }

            if (isSucc) {
                bw.write("YES\n");
            } else {
                bw.write("NO\n");
            }
        }

        bw.write(builder.toString());

        bw.close();
        br.close();
    }
}

• 정렬 문제
• 문자열로 정렬을 하면 바로 앞 문자열이 뒷 문자열의 접두어인지만 확인하면 해결된다.